Generally speaking, satellites comprise a series of pieces of equipment which, when functioning, generate heat that it is necessary to discharge effectively into cold space so that the temperature of this equipment remains within a nominal temperature range. The use of heat pipes to transport the heat generated by spacecraft equipment is commonly suggested. Heat pipes transfer thermal energy towards radiators. If the heat pipes form a fluid loop, the radiators can also be deployed thus to increase area of the radiating surfaces after the launch phase to ensure thermal control. More precisely, in a conventional thermal control system, equipment positioned inside satellites works at temperature ranges such that the discharge temperature of the energy dissipated into space via the radiator structures is limited by these ranges. For a given thermal energy to be removed the required radiating area (and therefore the thermal control mass) is therefore intimately linked to a limiting temperature level. Thus for very energetic missions the thermal subsystem becomes very large, since it is this which fixes the dimensions of the satellite (surfaces of the satellite walls), unless the use of bulky and heavy dedicated deployable structures is envisaged to increase the area of these radiating surfaces.
In fact, when the thermal discharge capacity of a satellite's walls is exceeded, the known solutions for removing the surplus dissipation are essentially the use of capillary fluid loops or mechanically pumped fluid loops linking the interior of the satellite to deployable radiators dedicated to thermal control. The latter are bulky and heavy. To this day (most of) these solutions and the associated European thermal products still require a qualifying phase in flight. The working temperature of the radiator or radiators (conventional or deployable) is necessarily lower than the maximum temperature acceptable for the equipment to be controlled, which impacts greatly on the dimensions required for these radiators and therefore limits the possibilities for their arrangement on the satellite.